Effects of absorption coefficients and intermediate-band filling in InAs/GaAs quantum dot solar cells

The effects of absorption coefficients were incorporated in a detailed balance model to analyze the intermediate-band (IB) configuration in quantum dot (QD) solar cells. Our results show that the optimum IB level, EIB, depends on the ratio of two subbandgap absorption coefficient constants, alpha(IC0)/alpha(VI0). Efficiency contour plots have been calculated to determine the optimum values of EIB and alpha(IC0)/alpha(VI0). In many cases, a large alpha(IC0) results in high conversion efficiency, especially for thin QD solar cells. Optimizing QD shape and size is a promising method to increase alpha(IC0). Increasing the QD total thickness partially addresses the urgent demand for a large alpha(IC0). (C) 2010 American Institute of Physics. [doi:10.1063/1.3516468]